LED's are mainly for long-term usage and heat restrictions. I have a small closet with a 4" intake fan and one house fan, running ~1200w (400w is HPS, 820w LED). If I were running ALL HPS the temps would be over 90F, but it runs a cool 78F. I've been using the same LEDs for almost a year now; they are rated at 10 year, but I'll give them 5 before they lose light. My HPS has already been through 2 bulbs this year (continuous growing), at 50-100$ apiece (depending on brand) that adds up quick.
5 years of HPS can run 500$ in bulbs. I paid that for my 450w LED. It should last just about as long, if not longer than 5 years worth of bulbs. On top of that, the power savings from the cooling bill put LED ahead; but, in the long term only.
But, if you need extra watts in a small space with ventilation restrictions, LED are the way to go.
Once prices of LEDs keep dropping, I believe that they will replace HPS for smaller scale grows soon (2000w and lower). HPS still dominates large scale. LED's just don't have the coverage yet.